Resize an Image by Percentage, Not Pixels

Most resize tools ask for exact pixel dimensions. That's fine when you know the number you need, and awkward when you don't — camera photos come in sizes like 4032×3024, and "make it about half" turns into unnecessary mental arithmetic.

Resize by Percentage takes the proportion instead. Set 50%, get an image half as wide and half as tall.

Why percentage is sometimes the better tool

• The aspect ratio can't break. Scaling both dimensions by the same factor keeps the proportions exactly right by construction — there's no way to accidentally stretch anything.
• Consistency across a batch. If you're processing photos of differing dimensions and want them all reduced by the same amount, percentage keeps them visually consistent. Forcing every image to identical pixel dimensions would distort whichever ones started with a different shape.
• It matches how you think. "This is about twice as big as it needs to be" is the actual thought. 50% is a direct expression of it.

The maths worth knowing

Percentage applies to each dimension, not to the area — and that catches people out. 50% means half the width and half the height, which is a quarter of the total pixels. That's a much bigger reduction than it sounds.

So 50% on a 4000×3000 photo gives 2000×1500 — 12 million pixels down to 3 million. It's why modest-sounding percentages produce dramatic file-size drops, and why small percentages get unusable faster than you'd expect: 25% of that same photo is 1000×750, and 10% is 400×300.

When exact dimensions are better

Percentage is the wrong tool when something specific is required of you. Use Resize Image with exact numbers when:

• A form or platform specifies exact pixel dimensions.
• You're targeting a known display width on a web page.
• You need several images to end up genuinely identical in size.

For social platforms, skip the arithmetic entirely — Resize for Instagram and Resize for YouTube Thumbnail already know the right numbers.

Don't scale up

The tool will let you go up to 500%, and you mostly shouldn't. Enlarging doesn't add detail — it interpolates new pixels from the existing ones and softens the image. A 200% scale-up of a small photo is a large blurry photo. Go back to the original at full resolution instead. Our guide to resizing covers this in more depth.

FAQ

Does 50% mean half the file size?
No — the file usually shrinks by considerably more than half. 50% halves each dimension, which leaves a quarter of the pixels, so the saving is far bigger than the number suggests.

Can I use a percentage over 100%?
The tool allows up to 500%, but you shouldn't expect much from it. Enlarging softens the image rather than adding detail — the detail isn't in the file to recover.

Percentage or exact pixels?
Percentage when you're scaling by feel or keeping a batch consistent. Exact pixels when something specific is required.